 /*******************************************************************************
  * Copyright (c) 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.filesystem.local;

 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.ProgressMonitorWrapper;

 /**
  * This class provides a simulation of progress. This is useful
  * for situations where computing the amount of work to do in advance
  * is too costly. The monitor will accept any number of calls to
  * {@link #worked(int)}, and will scale the actual reported work appropriately
  * so that the progress never quite completes.
  */
 public class InfiniteProgress extends ProgressMonitorWrapper {
     /*
      * Fields for progress monitoring algorithm.
      * Initially, give progress for every 4 resources, double
      * this value at halfway point, then reset halfway point
      * to be half of remaining work. (this gives an infinite
      * series that converges at total work after an infinite
      * number of resources).
      */
     private int totalWork;
     private int currentIncrement = 4;
     private int halfWay;
     private int nextProgress = currentIncrement;
     private int worked = 0;

     protected InfiniteProgress(IProgressMonitor monitor) {
         super(monitor);
     }

     public void beginTask(String name, int work) {
         super.beginTask(name, work);
         this.totalWork = work;
         this.halfWay = totalWork / 2;
     }

     public void worked(int work) {
         if (--nextProgress <= 0) {
             //we have exhausted the current increment, so report progress
 super.worked(1);
             worked++;
             if (worked >= halfWay) {
                 //we have passed the current halfway point, so double the
 //increment and reset the halfway point.
 currentIncrement *= 2;
                 halfWay += (totalWork - halfWay) / 2;
             }
             //reset the progress counter to another full increment
 nextProgress = currentIncrement;
         }
     }

 }

